score = (input("请输入成绩(1-100)："))
if score.isdigit():
    score_s = eval(score)
    if 90 < score_s <= 100:
        print("该等级为A")
    elif 80 < score_s <= 90:
        print("该等级为B")
    elif 60 < score_s <= 80:
        print("该等级为C")
    elif 0 <= score_s <= 60:
        print("该等级为D")
    else:
        print("输入范围不对！")
else:
    print("输入格式错误！")
